CVE-2016-0736

CVE-2016-0736 is a high-severity vulnerability in Apache Http Server with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 49% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-310.

Key facts

Description

In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto was encrypting its data/cookie using the configured ciphers with possibly either CBC or ECB modes of operation (AES256-CBC by default), hence no selectable or builtin authenticated encryption. This made it vulnerable to padding oracle attacks, particularly with CBC.

Frequently asked questions

What is CVE-2016-0736?
In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto was encrypting its data/cookie using the configured ciphers with possibly either CBC or ECB modes of operation (AES256-CBC by default), hence no selectable or builtin authenticated encryption. This made it vulnerable to padding oracle attacks, particularly with CBC.
How severe is CVE-2016-0736?
CVE-2016-0736 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2016-0736 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 49% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-0736?
CVE-2016-0736 primarily affects Apache Http Server. In total, 17 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-0736?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2016-0736 published?
CVE-2016-0736 was published on 2017-07-27 and last updated on 2026-06-17.

References

Affected products (17)

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Threat intelligence

Threat-intel indicators referencing this CVE: